Regensburg 2013 – wissenschaftliches Programm
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DF: Fachverband Dielektrische Festkörper
DF 12: Poster 1
DF 12.24: Poster
Dienstag, 12. März 2013, 10:30–13:30, Poster D
Magnetic and electric excitations of helices and Skyrmions in chiral magnets — •Johannes Waizner1, Markus Garst1, Achim Rosch1, Ioannis Stasinopoulos2, Thomas Schwarze2, Andreas Bauer3, Helmuth Berger4, Christian Pfleiderer3, and Dirk Grundler2,5 — 1Institute for Theoretical Physics, Univ. Köln, Köln, Germany — 2Physik Department, E10, TU München, Garching, Germany — 3Physik Department, FG Magnetische Materialien, TU München, Garching, Germany — 4EPFL, Institut de physique de la matiere complexe, Lausanne, Swizerland — 5STI, EPFL, Lausanne, Swizerland
An oscillating magnetic field induces precession in a ferromagnet resulting in a ferromagnetic resonance (FMR) that is described by the Kittel formula for a homogeneous magnetisation. We extend the theory of FMR to the case of chiral magnets, i.e., ferromagnets with a Dzyaloshinkii-Moriya interaction, taking into account the effect of demagnetisation fields. In the so-called conical phase, we find two magnetic modes whose weights depend on the polarisation of the driving magnetic field. In the Skyrmion lattice phase, several magnetic modes exist; we find that the mode with the largest weight has a smaller resonance frequency than the ones of the conical phase. As the Skyrmions carry polarisation in insulating chiral magnets, the modes can also be excited electrically. We compare our findings to recent experimental results.